Retaining Walls

retaining wall, petrovitsky & 117 ave se

 

The following is intended to help any applicant better understand the requirements and process of preparing, designing, and constructing a Retaining Wall, as required in the City of Renton.

 

Prepare

Do you Need a Permit?

A retaining wall that is 48" or taller, as measured by the vertical distance from the bottom of the footing to the finish grade at the top of the wall, always requires a building permit. Building permits also are required for any retaining wall 48" or less in height that supports a surcharge (any additional load bearing on or against the wall, such as fill material) behind or above the wall.


Retaining Wall Regulations

Allowable Materials

Retaining walls shall be composed of brick, rock, textured or patterned concrete, or other masonry product that complements the proposed building and site development. Other materials may be used with the Administrator’s approval.

Location Requirements

There shall be a minimum three‐foot 36" landscaped setback at the base of retaining walls abutting public rights‐of‐way from the property line - RMC 4-4-040 C.2.d.

Height Requirements

The maximum height of any residential retaining wall shall be 72", and is subject to further height limitations. Within the front yard setback, retaining walls cannot exceed 48" in height. On corner lots, walls shall not exceed 42" in height in any part of the clear vision areas and shall not exceed 48" within any part of the front yard setback or side yard along a street when located outside of any clear vision area.

Commercial or industrial retaining walls have a maximum height of 96" anywhere on the lot provided the fence, retaining wall or hedge does not stand in or in front of any required landscaping or pose a traffic vision hazard. 

How to Measure Retaining Walls

Provisions of RMC 4‐4‐040 states that Retaining Walls are measured by the “exposed retaining wall height,” which is the vertical distance measure from the finish grade at the bottom of the wall (i.e., lower soil grade) to the finish grade at the top of the wall.  The International Building Code measures from the bottom of the footing to the top of the wall, and any proposed wall taller than 48" must be designed by a Professional Engineer.

Terracing Retaining Walls

You can terrace your property. Terracing is the act of forming hillside into a number of level flat areas (terraces) between retaining walls.

  •  Terrace Width: No portion of a retaining wall shall be measured as part of the terrace width. The width of a terrace shall be equal to the height of the tallest abutting retaining wall; however, the minimum terrace width shall be 24" and the maximum required width shall be 60". Terrace width shall be measured from the back edge of the lower retaining wall to the foremost edge of the immediately succeeding and higher retaining wall and landscaped in conformance with the standards of RMC 4-4-070F.

Fences and Retaining Walls

If the fence/hedge would exceed the allowed height of a standalone retaining wall if placed on top of the wall, the fence/hedge shall be set back and landscaped at least 24".

Fences shall not be constructed on top of a retaining wall unless the total combined height of the retaining wall and fence does not exceed the allowed height of a standalone fence and a building permit is likely required. An exception may be allowed it the fence constructed is 72" or less and provides at least 50% transparency, as viewed perpendicularly to the face of the fence and is constructed outside the front yard and outside of the clear vision area. Chain link is not an eligible material.

Slope Retainage Requirements

Unless the wall is designed by a Professional Engineer, the slope of the ground being retained shall be level for a distance of at least 12" for each 12" of wall height. Soil may not be placed in front of the wall to reduce the exposed wall height.

diagram showing variations of fill for retaining walls

Guardrails and Retaining Walls

If the Building Official requires a guardrail, the combined height of the retaining wall and required guardrail shall not exceed nine 108" in residential zones, or 144" in commercial and industrial zones.

Modification Procedures

Pursuant to RMC 4‐9‐250D, Modification Procedures, the Administrator may grant modifications to this Section’s retaining wall standards. Approval of a modifications permit may include conditions such as, but not limited to, increased setbacks, additional landscaping, a requirement to terrace or specific materials to be used.


A diagram of required width and height of retaining wall     Retaining wall fig 2 depicts how to backfill a retaining wall

Resources 

Resources

• Geotechnical Report and/or Other Applicable Critical Areas Study - For properties located in or near critical areas (wetlands, steep slopes, coal mine hazards, creeks), contact the Planning Division at: 425-430-7294 or by email for information.

• Arborist Report - An Arborist Report is required for any site retaining less than 30% of existing trees. Waterfront properties or other lands covered by water must also submit an environmental checklist package and may have to apply for a shoreline exemption. Contact the Planning Division at: 425-430-7294 or by email for more information. 

Apply & Review

How to Apply

IF a building permit is required for your work, follow these steps when you are ready to submit your application and required documents and staff will supply you with a secure file share link

STEP 1:

Email the Project Name, Address and Scope of Work to:permittech@rentonwa.gov

STEP 2:

A Permit Specialist will reply with an FTP link to upload the required files

STEP 3:

Allow 5 days for initial application review.

STEP 4:

IF COMPLETE, you will be notified of acceptance and given payment instructions.

IF INCOMPLETE, you will be notified of incomplete requirements and instructions to proceed.

Tip: Review decisions may be significantly delayed by incomplete or inaccurate submittals. Closely follow the Submittal Requirements to prevent delays!


Review Response Times

Residential first review decisions are typically 2-3 weeks.
Residential revision decisions are typically 1-2 weeks.
Commercial first review decisions are typically 3-4 weeks.
Commercial revision decisions are typically 1-2 weeks.


Need Additional Help?

Schedule a Virtual Appointment
Email a Permit Specialist: Permittech@rentonwa.gov, or 
Call a Permit Specialist: 425-430-7215

Inspect & Complete

Once your permit is approved, you may begin work and scheduling inspections. Please print a copy of your permit to keep on-site for when your inspector arrives.


Scheduling Inspections

Inspections can be scheduled for the following business day online or by phone at: 425-430-7202.
Telephone Scheduling Help Guide


Day of Inspection

While we are unable to provide you a time window when scheduling, we are happy to assist on the day of the inspection:

STEP 1:

Using our Permit Portal, select "Today's Inspections".

STEP 2:

Locate your inspector's name and number by locating your permit (listed alphanumerically).

STEP 3:

Phone your inspector to request a time window for arrival.

Tip: See our "What to Expect from your Inspection"(PDF, 957KB)  help sheet to prepare for a successful inspection. 


Review Inspection Status and Notes

To see your inspection status and/or notes from a completed inspection:

STEP 1:

Log into our Online Permit Portal

STEP 2:

Using the search button, enter your permit number and select search.

STEP 3:

Your permit results will appear listing the status of the permit. Click on the blue permit number.

STEP 4:

Select "inspections" (center screen).

STEP 5:

Select the blue inspection number you wish to review.

STEP 6:

Select "Checklist" from the mid-screen menu.

Check out our "Check Inspection Status Online" tipsheet for screenshots and additional help accessing your permit details.